KR100610724B1 - Control apparatus for controlling load distribution in continuous rolling mill - Google Patents

Abstract

By simplifying the sheet thickness correction amount to a form that can be mounted during rolling, a load distribution control device for a continuous rolling mill which makes it possible to correspond to most of the calculation only during rolling is obtained.

When the rolling load ratio in each stand of the continuous rolling mill does not match the target load ratio, the load distribution controller 10 and the plate thickness which calculate the plate thickness correction amount of each stand according to the error from the target load ratio. The rolling position control system 7, 8, 9, which stores the rolling load ratio of each stand in accordance with the target load ratio and stores the rolling load ratio according to the correction amount, and the load distribution control device 10 is provided with respect to the rolling load variation. It is a load distribution control device of a continuous rolling mill that calculates the plate thickness correction amount of each stand during rolling using the vertical obtained by assuming that the sensitivity of the side plate thickness change and the rolling plate thickness change to the rolling load change are the same. .

Description

Load distribution control device for continuous rolling mill {CONTROL APPARATUS FOR CONTROLLING LOAD DISTRIBUTION IN CONTINUOUS ROLLING MILL}             

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing a load distribution control device for continuous pressure excitation according to Embodiment 1 of the present invention.

2 is a configuration diagram showing a load distribution control device for a continuous rolling mill according to Embodiment 2 of the present invention.

<Description of the symbols for the main parts of the drawings>

1, 1 ': rolling roll

2, 2 ': rolling roll

3, 3 ': rolling roll

4, 5, 6: rolling load detector,

7, 8, 9: pressure reduction position control system,

10: load distribution control device,

11: rolled material,

12: plate thickness correction amount calculation unit,

13 controller part.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load distribution control device for a continuous mill, and more particularly to a load distribution device for matching a distribution ratio of the rolling load of each stand in a continuous mill to its set value.

In general, the plate thickness reduction rate of each stand in a continuous rolling mill is determined so that the rolling load of each stand becomes a predetermined ratio in consideration of the thickness of the base plate, the plate thickness, the stable operation, the shape quality, etc. in addition to the rating of each mill. It is.

Due to the limitations of precision of rolling model, rolling mill characteristics, plastic deformation due to temperature change after rolling start, and other various appearances, the actual rolling load ratio is often inconsistent with the predicted value. The dimensional deviation, shape defect, rolling instability, rolling stop due to the equipment rating limit, and other inadequate. As for the deviation of the rolling load ratio, the mill operator monitors the rolling state and manually inserts the pressure lowering position to correct the deviation and to secure stable operation and shape quality.

For this reason, in recent years, technology for automatically securing an optimum load distribution, that is, a rolling load ratio, has been developed without resorting to manual intervention of the mill driver (see Patent Document 1, for example).

In the prior art of this document, when the rolling loads in each stand do not coincide with the ratio setting value of each other, the plate thickness correction amount of each stand is calculated from the error with the ratio setting value of the rolling load according to the rolling principle. The load distribution control method of correcting and matching and preserving the rolling load ratio of each stand to the setting value is mentioned.

Japanese Patent Application Laid-Open No. 2-39327.

In the above conventional technique, since the calculation of the plate thickness correction amount of each stand to be executed according to the principle of rolling from the error from the ratio setting value of the rolling load is a complicated calculation including the calculation of the retrograde force, the calculation load is taken. There was a problem that it could not be mounted.

Therefore, in the prior art, it is necessary to take a method of calculating a part executable before rolling before performing rolling and performing a simple calculation during rolling. In other words, since it was necessary to divide the calculation before rolling and the calculation during rolling, the work was complicated and some calculations were performed before rolling. For example, the target load ratio setting value should not be changed during rolling. There was a problem that the precision was not obtained sufficiently.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and to obtain a load distribution control device for a continuous rolling mill which makes it possible to carry out most of the calculation only during rolling by simplifying the calculation of the plate thickness correction amount to a form that can be mounted during rolling. The purpose.

The present invention relates to plate thickness correction amount calculation means for calculating the plate thickness correction amount of each stand according to an error from the target load ratio when the rolling load ratio of each stand of the continuous rolling mill does not match the target load ratio. And a rolling position control means for executing rolling position correction according to the plate thickness correction amount so as to save the rolling load ratio of each stand in accordance with the target load ratio, and the plate thickness correction amount calculating means includes the input to the rolling load variation amount. A load distribution control device for a continuous rolling mill that calculates, during rolling, the plate thickness correction amount of each of the stands using a predetermined first equation obtained by assuming that the influence of side plate thickness variation is the same.

Embodiment 1

Hereinafter, the load distribution control apparatus of the continuous rolling mill which concerns on Embodiment 1 of this invention is demonstrated according to FIG. Fig. 1 shows an optional istand of a continuous mill, a portion of an upstream i-1 stand and a downstream i + 1 stand. As shown in FIG. 1, each stand has a pair of rolling rolls which consist of an upper roll and a lower roll installed above and below. That is, the i-stand shown in the center of FIG. 1 possesses a rolling roll composed of an upper roll 2 and a lower roll 2, and similarly, the upstream i-1 stand is a rolling roll composed of an upper roll 1 and a lower roll 1 '. The downstream i + 1 stand has a rolling roll consisting of an upper roll and a lower roll 3 '.

At this time, the plate member 11 is rolled in the direction of the arrow of Figure 1 through the rolling rolls (1), (1 '), (2), (2'), (3) and (3 ') of the respective stands in order. Going.

Rolling load detectors 4, 5, and 6 are connected to the lower rolls 1 ', 2', and 3 'of the respective stands, respectively, so as to detect the rolling load on each stand. It is. In addition, the upper and lower rolls 1, 2, and 3 in each stand are provided with the pressure reduction driving devices 14, 15, and 16, and the pressure reduction position control systems 7, 8, and ( Rolling is performed in accordance with the roll gap change amount instruction command outputted from 9). In addition, each of the rolling load detectors 4, 5, 6, and the reduction position control systems 7, 8, and 9 are connected to the load distribution control device 10 (plate thickness correction amount calculating means). It is. The load distribution controller 10 inputs the rolling loads F _i-1 , F _i , F _{i + 1} in each stand detected by the rolling load detectors 4, 5, and 6, and accordingly Using the preset target load ratio {C _i-1 : C _i : C _{i + 1} }, the appropriate plate thickness correction amounts Δh _i-1 , Δh _i , Δh _{i + 1} at each stand are calculated. The plate thickness correction amounts Δh _{i -1} , Δh _i , Δh _{i + 1} , and the sheet thickness correction systems 7, 8, and 9 (pressing position control means) are the plate thickness correction amounts Δh _{i. -1,} △ h _i, h _{i + 1} △ rolgaep the correction amount, that is rolgaep change amount indicating S _i-1, S _i, the reduction drive unit 14 to change to the S _{i + 1,} (15) a, ( 16), load distribution control is realized.

The following operation is described. In this embodiment, in the load distribution control apparatus 10, the rolling loads in each stand of the continuous rolling mill detected by the rolling load detectors 4, 5, and 6 have their target load ratios set to each other. A determination is made as to whether or not {C _i-1 : C _i : C _{i + 1} } is matched, and when there is a mismatch, the sheet thickness correction amount of each stand is calculated according to the error from the ratio setting value of the rolling load. The pressure reduction position control systems 7, 8, and 9 perform pressure reduction position corrections according to the plate thickness correction amount, and perform load distribution control to keep the rolling load ratio of each stand in accordance with the set value. At this time, it is calculated during the rolling by using the formula obtained by assuming that the above-described plate thickness correction amount of each stand is equal to the influence of the side plate thickness on the rolling load and the influence of the side plate thickness on the rolling load is the same. have. This feature is described in detail below.

The rolling loads F _i-1 , F _i , F _{i + 1} detected by the rolling load detectors 4, 5, and 6 are always changed by the rolling situation, and the rolling load conversion ΔF _i is the plate thickness. When expressed as a relation with, the following equation (1) is obtained.

ΔF _i = Q _i ΔH _i -q _i Δh _i (i = 1 to N, Q _i > 0, q _i > 0)

Here, △ H _i is input side plate thickness variation, △ h _i is a sensitivity effect of △ H _i for the number of plate thickness amount (output side thickness change amount), Q _i is △ F _i, q _i is △ for △ F _i The sensitivity of h _i .

When the target load ratio between the stands is {C _i-1 : C _i : C _{i + 1} }, do not change the final stand plate thickness, that is, realize the target load ratio on the condition that Δh _N = 0 It is an object of the control of the present invention.

Assuming that the target load is F _i ^* and this is represented by the relational formula of F _i , ΔF _i , C _i , the following equation (2) is obtained.

F _i ^* = F _i + ΔF _i = C _i k (i = 1 to N, k: integer)

The following formula (3) is obtained from the relationship between the above formulas (1) and (2) and ΔH _i ΔΔh _i-1 .

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Here, the input side plate thickness of the first stand was set to △ H ₁ = 0.

Assuming that Q _i ≒ q _i , the equation (3) is modified to obtain an approximation of the following equations (4) and (5).

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As described above, in the present embodiment, rolling is carried out using the above equations (4) and (5) obtained by assuming that the influence sensitivity of the side plate thickness on the rolling load is the same as the influence sensitivity of the side plate thickness on the rolling load. hayeoteumeuro without calculating the inverse matrix is often troublesome to obtain the number of the plate thickness of the rolling load amount △ h _i to change, it is possible to calculate the plate thickness correction amount △ h _i. By using this calculation in the load distribution control device 10, no calculation load is applied, so that all calculations can be executed during rolling except Qi calculation, and the control method itself can be simplified.

(The calculation of Qi is not carried out under load distribution control, but is usually performed before rolling in automatic sheet thickness control. Therefore, the calculation result can be used.)

Further, since the calculation by the above equation (4) and (5), for example in advance is the target load ratio set during rolling in the rolling easily also change the _{{C i-1: C i} + 1: C i} It can be used for many purposes.

In the above description, an example in which the plate thickness correction amount is calculated using the above equations (4) and (5) has been described, but the plate thickness correction amount may be calculated using the above equation (3). Moreover, also in that case, calculation during rolling becomes possible and the equivalent effect is acquired.

Embodiment 2

Hereinafter, Embodiment 2 of this invention is described according to FIG.

In the drawings, 1 to 11 are the same as those in the first embodiment, and description thereof is omitted here. 2 differs from the first embodiment in that the plate thickness correction amount calculation unit 12 and the controller unit 13 are provided in the load distribution control device 10.

The plate thickness correction amount calculation part 12 calculates the plate thickness correction amount (DELTA) hi in each stand. The controller unit 13 is composed of a controller such as PI, and performs predetermined processing by the controller on the plate thickness correction amount Δh _i in each stand calculated by the plate thickness correction amount calculation unit 12, and integrates the term To a value that is the sum of and the proportional term. Therefore, in the present embodiment, the output value of the controller unit 13 becomes the final output from the load distribution control device 10.

In this embodiment, the rolling load in each stand of the continuous rolling mill detected by the rolling load detectors 4, 5, and 6 in the plate thickness correction amount calculation unit 12 (plate thickness correction amount calculation means). It is judged whether or not the set values of the target load ratios {C _i-1 : C _i : C _{i + 1} } are equal to each other. The thickness correction amount is calculated. Next, a predetermined function is processed on the plate thickness correction amount calculated by the controller unit 13 (final output plate thickness correction amount calculation means) to calculate the final output plate thickness correction amount consisting of two components, a proportional term and an integral term. do. Pressing position control systems (7), (8), (9) and (pressing position control means) perform the pressing position correction according to the final output plate thickness correction amount, and match the rolling load ratio of each stand to the set value. Load distribution control to save. The formula obtained by assuming that the above-described plate thickness correction amount of each stand is equal to the influence of the side plate thickness on the rolling load and the influence of the side plate thickness on the rolling load [Equations (4) and (5)] Or, it is calculated during rolling by using a formula (Equation (3)) obtained by assuming that the amount of change in the side plate thickness of an arbitrary stand is equal to the amount of change in the side plate thickness in an upstream stand adjacent to the stand.

It demonstrates in detail again. The plate thickness correction amount of each stand calculated by the plate thickness correction amount calculation unit 12 is called Δh _i . In the plate thickness correction amount calculation unit 12, the above formulas (4) and (5) obtained from the above relationship (3) or Q _i ≒ q _i obtained in the relationship of ΔH _i ≒ Δh _i-1 . Or the thickness correction amount Δh _i by the method according to the principle of rolling. The controller unit 13 calculates, for example,? Δ _i by a predetermined function f _controller as follows.

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Where Kp is the control gain of the proportional term, LAG {x} is the primary Lag, Ti is the control gain of the integral term, and s is the differential operator.

As described above, in the present embodiment, the same effect as in the first embodiment is obtained, and the controller by the controller unit 13 is controlled as in Equation (6) above without directly using the plate thickness correction amount Δh _i . By integrating, it is effective to speed convergence to the target value in the integral term, while in the proportional term, it is possible to directly correct by the calculation theory and to perform the first lag and cut the urgent operation to prevent the instability caused by interference with other control systems. There is an effect that can be prevented.

According to the present invention, by simplifying the calculation of the plate thickness correction amount to the form that can be mounted during rolling, most of the calculation can be performed only during rolling, and during rolling, for example, the target load ratio setting value can also be changed during rolling. .

Claims (3)

Plate thickness correction amount calculation means for calculating the plate thickness correction amount of each stand according to an error from the target load ratio when the rolling load ratio in each stand of the continuous rolling mill does not match the target load ratio, and the plate thickness A reduction position control means for correcting the reduction position according to the correction amount and keeping the rolling load ratio of each stand in accordance with the target load ratio; and the plate thickness correction amount calculating means includes the side plate thickness with respect to the rolling load variation. A rolling mill, characterized in that the rolling thickness correction amount of each of said stands is calculated during rolling by using a predetermined first equation obtained by assuming that the influence sensitivity of the change amount and the publication thickness change amount on the rolling load change amount are the same. Load distribution control device. The method of claim 1, When the stands are installed i (i = 1 to N) and the target load ratio between the stands is C _i-1 : C _i : C _{i + 1} , the predetermined first equation is

△ F _i = Q _i ㆍ △ H _i -q _i ㆍ △ h _i (Q _i > 0, q _i > 0) Where Δh _i is the plate thickness change (plate thickness correction) in the i-stand, ΔH _i is the plate thickness change, F _i is the rolling load, ΔF _i is the rolling load change, and Q _i is ΔF A load distribution control device for a continuous rolling mill, characterized in that the sensitivity of ΔH _i to _i . The method according to claim 1 or 2, And a correction amount calculating means for the final output plate thickness provided between the plate thickness correction amount calculating means and the pressing position control means, The correction amount calculating means of the final output plate thickness is a next function f _controller that calculates a final output plate thickness correction amount Δh _i ^out to the plate thickness correction amount calculated by the plate thickness correction amount calculating means. To perform the calculation,

Where Kp is the control gain of the proportional term, LAG {x} is the primary Lag, Ti is the control gain of the integral term, and s is the differential operator. A load distribution control device for a continuous rolling mill, characterized in that it calculates a correction amount of the final output plate thickness consisting of two components, a proportional term and an integral term.

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